Valve for compressed air circuit breakers



July 17, 1 1 H. FORWALD 2,561,192

VALVE FOR COMPRESSED AIR CIRCUIT BREAKERS Filed Jan. 17, 1948 2 Sheets-Sheet l Fiql July 1951 H. FORWALD 2,561,192

VALVE FOR COMPRESSED AIR CIRCUIT BREAKERS Filed Jan. 17, 1948 2 Sheet-Sheet z //7 K917 7 0r f/aakan HEW/d Patented July 17, 1951 VALVE EOR COMPRESSED AIR CIRCUIT BREAKERS Haakon Forwald, Valhalla, Ludvika, Sweden, assignor to Allmanna Svenska Elektriska Aktiebolaget, Vasteras, Sweden, a Swedish corporation Application January 1'7, 1948, Serial No. 2,922 In Sweden May 20, 1944 Section 1, Public Law 690, August 8, 1946 Patent expires May 20, 1964 2 Claims.

The present invention relates to a compressed air circuit breaker in which an air blast valve is arranged in close proximity to the breaking gap and in spite of this fact can be made from material giving a perfect sealing efiect, so that the consumption of compressed air is reduced to a minimum. The invention is applied to air blast circuit breakers of the type having a nozzle in which the interruption arc is brought in contact with the extinguishing air. According to the invention, an annular valve seating is arranged around this nozzle on the inlet side thereof, and the movable contact is provided with a valve member, which is forced against this seating when the contacts of the breaker are closed.

On the accompanying drawings, two modifications are shown. Fig. 1 shows, in vertical section, a circuit breaker in which the said valve seating is arranged around the inlet opening in a nozzle contact. Fig. 2 shows part of a breaker of a modified form in which the movable contact is, to a certain extent, movable in relation to the valve member connected to it.

In Fig. 1, I designates the stationary contact of the circuit breaker in which an opening or nozzle l is formed in the contact. The lower end of this nozzle is surrounded by an annular valve seating 2. The movable contact 3 of the circuit breaker is rigidly connected to a valve member 4, the upper edge of which may be forced against the seating 2. The movable contact 3 is conductively connected by the slip contact 5 with one terminal of the circuit breaker, and when the breaker is closed, the movable contact 3 is held in contact with the contact I by the spring 5', which tends to move upwardly the valve member 4 and the contact 3 attached there to. When the circuit breaker is closed, the interior thereof is in communication with the compressed air container 1, which has the advantage that the air in the inner space I of the circuit breaker is always dry, and due to this fact and due to the high pressure of the air, the insulating distances inside the circuit breaker can be kept quite small. When operating the circuit breaker, the contact operating valve 8 is moved to the right, by means of the breaker operating mechanism 9, and the inner air space I is thus opened to the atmosphere so that the pressure in the circuit breaker, acting on the valve member 4, will then move it downwardly together with the contact 3 connected thereto. Simultaneously or immediately before the contact 3 separates from the contact I, a slot is formed between the upper edge of the valve member 4 and the seating 2, so that the arc between the contacts I and 3 is exposed to a powerful flow of air.

The arrangement shown in Fig. 2 differs from the other only in that the movable contact 3 is movable in relation to the valve member 4. The member 4 is normally forced upwards by the spring l2, so that its upper edge is forced against the seating 2, and the contact 3 is forced by the spring l3 against the stationary contact I. The movable contact 3 is, by means of the part l4 and the sliding contact l5, conductively connected with one terminal of the circuit breaker. When the valve 8 is opened, the pressure in the circuit breaker will act on the member 4 and move it downwards, so that a slot is formed between the seating 2 and the upper edge of the member 4. When the member 4 moves a short distance downwards, its inner shoulder strikes the collar on the contact 3 and by impact loosens it from the contact I. This arrangement has the further advantage that, if the contacts I and 3 are welded together, this welding is broken by the impact exerted by the member 4 on the contact 3, and the still further advantage is obtained that the member 4 already has a considerable speed, before it strikes the contact 3, so that the contact 3 will get an increased initial speed when opened.

I claim as my invention:

1. A compressed air circuit breaker comprising a stationary contact, a movable contact, means delivering arc extinguishing air to said contacts, a nozzle traversed by said are extinguishing air in contact with the are between the contacts, a valve seating on said stationary contact in close proximity to the inlet side of said nozzle, a valve member connected to the movable contact and forced against said seating when the contacts are in their closed position.

.2. A compressed air circuit breaker comprising a stationary contact, a valve seating on said contact, a movable contact, an annular valve member engaging said seating and carried with and movable in relation to said movable contact, and operating means for the movable contact whereby initial movement of the movable contact away from the stationary contact is preceded by movement of said annular valve member away from the said valve seating, and whereby further movement of the movable contact and annular member is in unison.

I-IAAKON FORWALD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,262,516 Prince Nov. 11, 1941 2,280,321 Thommen Apr. 21, 1942 2,367,934 Flurscheim Jan. 23, 1945 

